Metal treating compositions



Patented Sept. 12, 1950 2,521,783 METAL TREATING COMPOSITIONS John D. Farber, Philadelphia, Pa.

No Drawing. Application April 1, 1949,

Serial No. 85,041

7 Claims. 1

' This invention relates to a composition for the heat treatment of metals, and more particularly relates to a composition containing coal tar, water, petroleum derivatives and a filler for application to hot metal in preparation for subsequent operations in which the shape of the metal is changed.

Quenching, drawing and other heat-treating compounds containing various petroleum products and derivatives have been proposed for specialized purposes in connection with the treatment of various metals. Many of these compositions function as coolants and provide means for controlling to some degree the resultant hardness of the metal being treated. However, in practical use the coolants of the prior art are generally removed from the surface of the heat-treated metal prior to subsequent working. I have discovered a new composition for heat treating metals and have further discovered that when a hot metal is placed in my composition, an interaction of ingredients takes place in my composition and causes deposition of a coating on the treated metal which enhances the tensile strength of the metal as attained by a subsequent deformation at a reduced temperature. The subsequent working may takeplace at any desired temperature below the initial high temperature, and is referred to herein as cold working. Little thought has heretofore been directed to the possibility of controlling the strength of a metal as measured after cold working by means of a residue deposited in a previous heat treating operation, prior to the cold working step. It is particularly to this phase of the metallurgical art that my invention is directed.

It is an object of this invention to provide a new composition for heat treatment of metals. It is a further object of this invention to provide convenient means for enhancing the strength of a heat treated metal during cold rolling. A still further object of my invention is to provide a composition which when applied as a coolant to hot metal deposits a coating thereon, whereby enhanced strength of the metal is attained on subsequent deformation of the metal at a reduced temperature. Other objects and means for carrying them into effect will appear hereinafter.

The compositions of my invention contain a refined coal tar, water, a petroleum derivative, and a filler. While the various proportions of these ingredients vary somewhat, it may be stated that coal tar is a major constituent and that water is similarly present in rather substantial proportions. While it is not entirely necessary, I attain Per cent Benzene and its homologues 2.50 Phenol and-its homologues 2.00 Pyridine and quinoline bases 0.25 Naphthalene and acenaphthene v 6.00 Heavy oil 20.00- Anthracene and phenanthrene 2.00, Pitch 62.00 Ammoniacal liquor 4.00 Gases and loss 1.25

Total 100.00

In the refining process the crude coal tar is first dehydrated by settling and heating quietly under pressure or by heating a thin stream of coal tar in a vacuum. From the dehydrator the coal tar is conducted to a still and the temperature in the still is radually increased to remove residual water, light oils, middle oils and creosote oils, at maximum temperatures of about l-230 C. The refined residue is a product varying in consistency from a thin to a more or less viscous liquid. It is this product, known as refined coal tar, or distilled coal tar that I incorporate in my new heat treating compound. Its chemical constitution is dependent upon the nature of the coal from which it is produced, the nature of the coal distillation, and the nature of the crude tar distillation. It may be stated, however, that refined coal tar containing coal tar pitch, heavy oil, anthracene oil, and phenanthrene falls within the compositions of my invention.

The petroleum derivative which constitutes an ingredient of my composition is a liquid fraction produced in the distillation of petroleum oil and may be a relatively volatile oil such as a gasoline or kerosene fraction or a slightly less volatile oil such as fuel oil of varying viscosity or an oil having a viscosity up to about 375 Engler at F. and above. It is possible to use even heavier oils particularly when the refined coal tar tobe combined with the oil is relatively thin. The liquid petroleum derivatives having higher boiling temperatures than kerosene are referred to herein as fuel oils and are particularly desirable liquid petroleum derivatives in compositions of this invention. The term petroleum oil is used herein to define oils ranging in viscosity and flash point from gasoline fractions to heavy fuel oil fractions.

Combined with the other ingredients of my composition is-a 'flnely dividedinertfiller; 'The specific compositions of many inert fillers suitable for incorporation in petroleum and coal products are known. As examples of suitable fillers it is possible to use chalk, talc, whiting, vermiculite, ochre, powdered asbestos, powdered mica, pyrophyllite and the like with good resultsbut. itis particularly preferred to incorporatejn mycompositions an inert filler known as caliche filler which I define as a crude nitrate or Chile saltpeter containing about 20-50% NaNOa andvary- Y ing minor amounts of sodium iodate. Whatever inertflller is used, it. should preferably be;finely divided and it is also preferable that it be sufliciently fineethat a major .proportionifznot'the entire mass passes through a standard325i-mesh screen.

Zincchloride 'of'a commercial grade is preferred as' a further'ingreidient'of my .=composition, although it will :be understood that excellent results maybe obtained in some caseswhen no zincchloride is present. I-Iig'h'lyrefined zinc chloridesas well asrelativelycrudeicompounds are found to be effective and may if desired constitute an ingredient of my composition.

The compositions of my invention are convenientlyprepared by mixing the filler and-zinc chloride (if any) into the water, and then adding this mixture to a blend of refined coal tar and the selected petroleum derivative. The aqueous mix and the oil-coal tarblend' are-then mixed thoroughly to form a suspension and the mix thus obtained constitutes the heat'treating and 'cold forming compound of this invention. Frequent agitation of the mix may be desired if relatively rapid separation of phases is encountered.

The proportions of ingredients of compositions of this. invention. maybe varied considerably without: substantial reduction of. effectivenessbut I prefer to use a composition in which the following proportions of ingredients are present:

' through 325 mesh).

' Per cent Refined coal tar. -45. Fuel oil 1.0-20 Calichefiller (325 mesh) 5-25. Water- 10-45 I find: that undermany conditions it is still morepreierable to incorporate zinc chloride into my compositions and that enhanced-strength is attained. in a cold-deformed steel by this means.

Preferred proportions:v of ingredients of compositionsincludingzinc chloridefall within thefollowing ranges:

Incuse, my compound is placed in a container, a pieceof steel is heated to a cherry red. color and is immediately dipped into thecompound. A.

controlled chillingof the-metal takes place and theqmetali-is removedfrom the compoundgafterrestricted thereby except as specified a short period of time. The metal is then cold worked, bent or moulded while my new compound remains attached to the surface of the metal. On completion of the cold deformation step the metal has acquired a greater strength than it had prior to treatment in an amount surprisingly greater than would be expected.

As an illustration of one of many methods of practicinggmy invention; the following example is'set forth.

Example 35' pounds of completely dehydrated refined coal tar are blended with 12 pounds of a good grade Diesel engine fuel oil in a 55 gallon drum. .Into a separate drum containing 30 pounds of water are placed 10 pounds of commercial grade zinc chloride and 13 pounds of caliche filler The aqueous mix is then poured into the oil and tar container and the resultingacontents are thoroughly mixed by means of a mechanical stirrer. A medium steelbarzds heated-to a cherry red glow, dipped into themix', and held. in intimate contact with the mix for .40 seconds. On removal the bar is cold rolled to form a rod of circular. cross section while the surface of the metal remains covered with-.the'composition of the invention. The tensile strength of the product as tested on a standard testing machine is considerably greaterthan'the strength of similar rods treated with other compounds.

The reasons underlying the success of my compound are not well established as yet. However it seems probable that the sudden high temperature attained locally in my composition by "the sudden immersion of the hot steel object initiates a chemical interaction resulting in-the'deposition on the metal surface of a compound that enhances the effect of cold working on the strength of steel.

While specific quantities and proportions have been stated herein, it is to be understood that these-figures represent merely preferred embodiments of my invention. I do not intend to be in the claims.

1. A composition for the .heat treatment of metals and subsequent conditioningof said metals during deformation at reduced temperature, which consists essentially of the. following ingreclients in substantially the weight proportions stated:

Per cent Refined coal tar 30-45 Fuel oil 1.0-20 Caliche filler (fine) 5 -25 Water 10-45 2. A composition for the heat treatment-of metals and subsequent conditioning of, saidmetalsduring deformation at reduced temperature, which consists essentiallyof the follcwingingreclients in substantially the weight proportions stated:

Bencent. Refined coal tar 30-40 Fuel oil 8-15 Caliche fille (fine) 5-20 Zinc chloride j5-l2 Water 10-40 3. A compositionfor heat treatment of metals, consisting essentially of 30-45% by weight dehydrated refined coal tar residue, 10-20% by weight fuel oil constituting a distillation fractionofpetroleum oil and. having-a minimum boiling temperature higher than that of kerosene, 5-25% by weight finely divided inert filler, and 10-45% by weight Water.

4. A composition for heat treatment of metals, consisting essentially of 30-45% by weight dehydrated refined coal tar residue containing a major proportion of coal tar pitch, 10-20% by weight fuel oil constituting a distillation fraction of petroleum oil and having a minimum boiling temperature higher than that of kerosene, 5-25% by weight finely divided inert filler, and 10-45% by weight water.

5. A composition for heat treatment of metals, consisting essentially of 30-45% by weight dehydrated refined coal tar residue, 10-20% by weight fuel oil constituting a distillation fraction of petroleum oil and having a minimum boiling temperature higher than that of kerosene, 5-25% by weight finely divided inert filler capable of passing through a standard 325-mesh screen, and

y of kerosene, 5-25% by weight finely divided filler inert in the presence of red hot metal, and 10-- 45% by Weight water.

'7. A composition for heat treatment of metals and subsequent conditioning of said metals at reduced temperature, consisting essentially of 30- 40% by weight dehydrated refined coal tar resi- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,738,776 Kirschbraun Dec. 10, 1929 FOREIGN PATENTS Number Country A Date 19,475 Australia Sept. 20, 1935 OTHER REFERENCES Water-Gas Tar Emulsions, pages 36 and 37; Technical Paper No. 304, Department of Interior.

Published in 1923 by the Government Printing Ofiice, Washington, D. C. 

1. A COMPOSITION FOR THE HEAT TREATMENT OF METALS AND SUBSEQUENT CONDITIONING OF SAID METALS DURING DEFORMATION AT REDUCED TEMPERATURE, WHICH CONSISTS ESSENTIALLY OF THE FOLLOWING INGREDIENTS IN SUBSTANTIALLY THE WEIGHT PROPORTIONS STATED: 